268 
iSidney I. Kornhauser. 
early prophase, ^Yhich later straigliteus out to form the large tetrad of the 
first spermatocyte. Eight smaUer tetrads are formed in each species, 
and these correspond to sixteen small chromosomes of the spermatogonia. 
The allosomes, however, differ greatly in the two species; E. binotata 
lias an equal pair of allosomes ; E. curvata has a single a:-chromosome, 
\Yhich is of about the size of one of the allosomes of E. binotata. The be- 
havior of the allosome pair in E. binotata shows that it resembles to a 
great extent the autosome pairs, inasmuch as its components lie parallel 
for a considerable period and finally form a double chromosome in the 
early prophase. The argunients for considering them allosomes have 
beeil given in the description of E. binotata. They were there designated 
as the xy pair, x being richer in stainable substance and remaining com- 
pact throughout the growth period; y being more granulär, looser in 
texture and less easily recognized in the strepsinema and early tetrad 
formation. 
In E. curvata there is a typical unpaired .'C-clu'oniosome recognizable 
during the entire growth period. It is often in direct connection with 
two or tliree chromatic nucleoli, which stain deeply and are connected 
by linin fibers to the double autosome thi-eads. It was shown that these 
nucleoli disappear in the late strepsistene stage by a gradual loss of chro- 
inatin. The a;-element forms a spherical and deeply staining chromosome, 
which shows its future plane of division only in smear preparations. It 
is also characterized by distinct linin fibers connecting it to neighboring 
tetrads. These fibers are again in evidence at the first maturation division. 
Comparative Suniniary up to the First Maturation Division. 
Enchenopa hinoiata 
Enchenopa cunata 
Spermatogonia] 1 f 
2 macrocliromosomes 
2 macrochromosomes 
Chromosomes j |l8 smaller chromosomes 
17 smaller chromosomes 
Total : 
>0 
19 
Growth Period of Spermatocyte 
Autosomes 
T long double thread 
1 long double tluvad 
8 shorter double threads 
8 shorter double threads 
Allosomes 
1 pair allosome threads 
1 a:-chromosome -1- 2 or 3 chro- 
{xy pair) 
matic nucleoli 
fl large tetrad 
1 large tetrad 
Prophase of| 
First Sper-> 
8 small tetrads 
8 small tetrads 
2 small allosomes, xy pair, 
1 small spherical x-chromosome 
connected to each other 
connected to tetrads by dis- 
matocyte | 
by a thick deeply stain- 
ing Strand. 
tinct linin fibers. 
